boards: arm: apollo4p_blue_kxr_evb: Move the bt-spi instance to soc dts

Since the pins of bt-spi instance are wired internally in the chip, it will
make sense to move the definition to soc dts so no need for every board
using the chip to redefine the same.

Signed-off-by: Aaron Ye <[email protected]>

Author: aaronyegx

boards/arm/apollo4p_blue_kxr_evb/apollo4p_blue_kxr_evb.dts

@@ -87,20 +87,9 @@
 };
 
 &iom4 {
-	compatible = "ambiq,spi";
 	pinctrl-0 = <&spi4_default>;
 	pinctrl-names = "default";
-	cs-gpios = <&gpio32_63 22 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
-	clock-frequency = <DT_FREQ_M(24)>;
 	status = "okay";
-
-	bt-hci@0 {
-		compatible = "ambiq,bt-hci-spi";
-		reg = <0>;
-		irq-gpios = <&gpio32_63 21 GPIO_ACTIVE_HIGH>;
-		reset-gpios = <&gpio32_63 23 GPIO_ACTIVE_LOW>;
-		clkreq-gpios = <&gpio32_63 20 GPIO_ACTIVE_HIGH>;
-	};
 };
 
 &mspi0 {

dts/arm/ambiq/ambiq_apollo4p_blue.dtsi

@@ -160,13 +160,25 @@
 			ambiq,pwrcfg = <&pwrcfg 0x4 0x10>;
 		};
 
-		iom4: iom@40054000 {
+		iom4: spi@40054000 {
+			/* IOM4 works as SPI and is wired internally for BLE HCI. */
+			compatible = "ambiq,spi";
 			reg = <0x40054000 0x1000>;
 			#address-cells = <1>;
 			#size-cells = <0>;
 			interrupts = <10 0>;
+			cs-gpios = <&gpio32_63 22 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
+			clock-frequency = <DT_FREQ_M(24)>;
 			status = "disabled";
 			ambiq,pwrcfg = <&pwrcfg 0x4 0x20>;
+
+			bt-hci@0 {
+				compatible = "ambiq,bt-hci-spi";
+				reg = <0>;
+				irq-gpios = <&gpio32_63 21 GPIO_ACTIVE_HIGH>;
+				reset-gpios = <&gpio32_63 23 GPIO_ACTIVE_LOW>;
+				clkreq-gpios = <&gpio32_63 20 GPIO_ACTIVE_HIGH>;
+			};
 		};
 
 		iom5: iom@40055000 {